Influence of a TiO2 adhesion layer on the structure and the orientation of a Pt layer in Pt/TiO2/SiO2/Si structures

Three kinds of TiO2 layers were formed on SiO2/Si substrates: (200)-oriented TiO2 with rutile structure, (103)-oriented TiO2 with anatase structure and randomly oriented TiO2. All the Pt films deposited on the TiO2 layers had (I 11) orientation. Pt films deposited on the rutile TiO2 had a columnar structure and the full-width at half maximum (FWHM) of the rocking curve of the Pt(I 11) plane was estimated to be 0.88degrees. The diffusion of TiO2 to the surface of the Pt films hardly occurred in the case of rutile TiO2. The FWHM of the rocking curve of Pt(l 11) formed on anatase TiO2 was estimated to be 1.55degrees. The rocking curve of Pt(l 11) formed on randomly oriented TiO2 consisted of two peaks with centers separated by 6.25degrees. The diffusion of TiO2 to the surface was observed in the cases of anatase and randomly oriented TiO2. From these results, we concluded rutile TiO2 fabricated by metal deposition and subsequent oxidation was the best material for high-quality bottom Pt electrodes.